Respiratory system MCQs (Physiology practice multiple choice questions for FCPS, MRCP, USMLE, and PLAB)

Respiratory system MCQs

1) In Caissons disease pain in the joints and muscles is due to

a. formation of N2 bubbles         

b. formation of CO2 bubbles

c. due to fatigue              

d. due to increase in barometric pressure

Ans. a

2) Normal value of FEV1 in an adult is

a. 95%  

b. 80%

c. 65%  

d. 50%

Ans. b

3) The most important gas maintaining alveolar ventilation is

a. oxygen           

b. hydrogen

c. carbon dioxide             

d. N2

Ans. c

4) Hyperbaric oxygen is useful in all except

a. congenital heart disease         

b. gas gangrene

c. CO poisoning                

d. N2 toxicity

Ans. d

5) Administration of O2 is of value in all except

a.  cytotoxic hypoxia      

b. stagnant hypoxia

c. anaemic hypoxia         

d. histotoxic hypoxia

Ans.  d

6) As one ascends to higher than 3000meters above sea level changes in alveolar PO2 and PCO2 are as follows

a. decrease in PO2, increase in PCO2      

b. decrease in PO2, decrease in PCO2

c. increase in both PO2 and PCO2            

d. increase in PO2, decrease in PCO2

Ans. b

7) Surfactant is secreted by

a. type 1 pneumatocytes             

b. type 2 pneumatocytes

c. goblet cells    

d. pulmonary vessels

Ans. a

8) Which of the following effects is not observed during prolonged stay is space

a. decrease in blood volume      

b. decrease in muscle strength

c. increase in red cell mass          

d. loss of bone mass

Ans. c

9) Which of the following discharge spontaneously during quiet breathing

a. stretch receptors in lung         

b. motor neurons in respiratory muscles

c. dorsal respiratory group of neurons   

d. ventral respiratory group of neurons

Ans. c

10) Pneumatic center functions primarily to

a. limit inspiration           

b. prolong expiration

c. decrease rate               

d. discharge inspiratory action potentials

Ans.a

11) Which of the following is the effect of negative G on the eye

a. temporary blinding with redout           

b. blackout of vision within few seconds

c. no effect        

d. redout and blackout

Ans. a

12) Airway resistance

a. increases in asthama                

b. decreases in emphysema

c. increases in paraplegic patients            

d. does not affect work of breathing

Ans. a

13) Decrease on PCO2, decrease in H+ and increased PO2 causes

a. hyperventilation         

b. hypoventilation

c. hypercapnoea             

d. hypoxia

Ans. b

14)  Herring-Breur inflation reflex in human being

a. decreases the rate of respiration        

b. is not activated until the tidal volume increases above 1.5 lit

c. is an important factor in normal control of ventilation

d. is activated only when tidal volume is les than 1 lit.

Ans. b

15) Total vital capacity is decreased but timed vital capacity is normal in

a. bronchial asthama     

b. scoliosis

c. chronic bronchitis       

d. all the above

Ans. b

16) The intrapleural pressure at the end of deep inspiration is

a. - 4mm Hg       

b. + 4 mm Hg

c. - 6mm hg        

d. + 6 mm Hg

Ans. a